Question

Que. (5) An object is placed at a distance of 30 cm from a concave mirror of focal length 15 cm
write the the position nature and size of image ?​

Answer 1

Given :

Distance of object = 30 m

Focal length = 15cm

Type of mirror : concave

To Find :

Position and nature of the image.

Solution :

⧪ Focal length of concave mirror is taken negative and that of convex mirror is taken positive$.$

Position of image can be calculated by using mirror formula which is given by

• 1/v + 1/u = 1/f

v denotes distance of image

u denotes distance of object

f denotes focal length

By substituting the given values!

➠ 1/v + 1/u = 1/f

➠ 1/v + 1/(-30) = 1/(-15)

➠ 1/v = -1/15 + 1/30

➠ 1/v = (-2 + 1) / 30

➠ v = -30 cm

⧪ Nature of image :

• Real
• Inverted
• Same size

[Note : Size of image can't be calculated as size of object is not given in the question]

Answer 2

Given :

Distance of object = 30 m

Focal length = 15cm

Type of mirror : concave

To Find :

Position and nature of the image.

Solution :

⧪ Focal length of concave mirror is taken negative and that of convex mirror is taken positive..

Position of image can be calculated by using mirror formula which is given by

1/v + 1/u = 1/f

v denotes distance of image

u denotes distance of object

f denotes focal length

By substituting the given values!

➠ 1/v + 1/u = 1/f

➠ 1/v + 1/(-30) = 1/(-15)

➠ 1/v = -1/15 + 1/30

➠ 1/v = (-2 + 1) / 30

➠ v = -30 cm

⧪ Nature of image :

• Real

• Inverted

• Same size